Face mask with enhanced seal and method

ABSTRACT

A face mask is provided that includes a filter body capable of filtering liquids, particles and aerosols of a size appropriate for the mask&#39;s intended purposes, while providing excellent breathability and comfort for extended periods of time. The filter body may be formed from multiple layers of filtration material having a generally rectangular configuration with a plurality of pleats. The mask may be secured to the head of a wearer by tie strips attached to flaps extending from the filter body to form a fluid seal between the periphery of the mask and the wearer&#39;s face. For some applications, the flaps may be formed from resilient or stretchable material which further enhances both the fluid seal formed by the mask and comfort for the wearer. A clear visor may also be attached to the mask to protect the wearer&#39;s eyes and portions of the wearer&#39;s face not covered by the mask.

This application is a divisional application of U.S. application Ser.No. 08/278,930, filed Jul. 20, 1994 and entitled Face Mask With EnhancedSeal and Method, now U.S. Pat. No. 5,553,608 issued Sep. 10, 1996.

TECHNICAL FIELD OF THE INVENTION

This invention relates in general to medical products, and inparticular, but not by way of limitation, to a face mask with anenhanced seal to prevent fluids and aerosols from contacting the face ofa wearer. Various types of visors or shields may be attached to the maskto prevent liquids from contacting the eyes of the wearer.

BACKGROUND OF THE INVENTION

Wearing protective face masks has become standard procedure for manyhealth care and other related activities. The use of a face mask isimportant, for example, to lab technicians while conducting tests, tonurses during the care of patients, to physicians during surgery andother types of medical treatment, and to dentists working in a patient'smouth.

The rapid increase of infectious diseases, particularly AIDS, has madethe use of such protective equipment increasingly important. The Centerfor Disease Control in Atlanta, Ga., has found that the AIDS virus (HIV)can be passed by contact with body fluids. Contact of AIDS contaminatedbody fluids with another person's source of body fluids, e.g., eyes,nose, mouth, etc., can pass the disease. Therefore, it is necessary toprevent a patient's body fluids from contacting the face of health carepersonnel.

During the past several years, health care personnel have become moreaware of the potential hazards associated with airborne pathogens, suchas the hepatitis B virus and infectious tuberculosis associated withmany HIV patients. It has been found that aerosols having airborneliquid and solid particles are generated not only by the exhalation ofinfected patients, but also by certain procedural manipulations andprocesses that impart energy to microbial suspensions. Also many viralhemorrhagic fevers such as yellow fever, rift valley fever and perhapsrocky mountain spotted fever, rabies and smallpox can be transmittedthrough aerosols. A considerable number of studies have been made whichare now beginning to identify the transmission of viruses through"non-accident" situations. Accordingly, there is an increased interestin a face mask which will form a complete fluid seal around theperiphery of the mask and at the same time be easy to put on andcomfortable to wear. Many face masks which are presently available allowthe passage of fluids and/or aerosols between the periphery of the maskand the wearer's face.

One type of face mask is illustrated in U.S. Pat. No. 2,012,505 entitledMask, issued on Aug. 27, 1935 to S. J. Goldsmith. Another type of facemask is illustrated in U.S. Pat. No. 4,319,567 entitled Disposable FaceMask, issued on Mar. 16, 1982 to M. Magidson. This mask is molded andhas been especially configured in an effort to avoid leakage of fluidflow past the edges of the mask. Obviously, leakage cannot be toleratedwhen attempting to control liquids and aerosols. Typically surgicalstyle pleated face masks may have less than an optimal fit to preventthe passage of liquids and/or aerosols between the periphery of the maskand a wearer's face. Recent developments in surgical face masks haveresulted in improved resistance to liquid penetration from the exteriorof such masks. U.S. Pat. No. 4,920,960 entitled Body Fluids BarrierMask, issued on May 1, 1990 to Hubbard, et al., is exemplary ofimprovements in such masks.

SUMMARY OF THE INVENTION

In accordance with the present invention, an improved face mask isprovided to substantially reduce or eliminate the shortcomingspreviously associated with surgical style face masks. A shield or visormay be attached to the improved face mask in accordance with one aspectof the present invention.

The present invention provides a surgical style face mask which inhibitsthe passage of fluids between the periphery of the mask and the wearer'sface while providing enhanced comfort to the wearer. The presentinvention may be used with standard pleated style face masks,off-the-face style masks, or molded cone style masks. For someapplications, a single pair of ties may be used to secure a maskincorporating the present invention with the head and face of thewearer. For other applications, a mask incorporating the presentinvention may be secured to the head and face of the wearer with adouble pair of ties or four surgical tie strips. For still furtherapplications, a mask incorporating the present invention may be securedto the head and face of the wearer with a continuous loop of resilientmaterial. Fluid impervious flaps are included to extend the coveragearea of the face mask and improve the fluid seal between the peripheryof the mask and the face of the wearer. The fluid impervious flaps alsoallow reducing the amount of filter media associated with each face maskwhile maintaining the same amount of effective filtration area andbreathability.

One aspect of the present invention provides a face mask having a filterbody for covering the nose and mouth of a wearer. The filter body hastop and bottom edges with the top edge arranged to extend across thebridge of the nose of the wearer and the bottom edge arranged to extendunder the wearer's chin. Fluid impervious flaps extend from each side ofthe filter body for use in attaching the mask to the wearer's face andto provide an enhanced fluid seal between the periphery of the mask andthe wearer's face. A securing means may be attached to the respectiveflaps extending from each side of the filter body. The securing meansmay be extended over the head of the wearer for use in urging the topand bottom edges of the filter body and the flaps on each side of thefilter body into tight engagement with the wearer's face to preventundesired fluid flow between the periphery of the mask and the wearer'sface. The securing means may preferably be formed from resilientmaterial to provide comfort to the wearer while maintaining a tightperipheral seal for long periods of time. The securing means may beformed from other types of material as desired. For one application ofthe present invention, a first and second securing means associated witheach flap may be crossed over each other to further enhance the fluidseal formed by the periphery of the mask with the wearer's face.

Another aspect of the present invention provides a face mask having aplurality of layers of selected material which are resistant to thepassage of aerosols and/or liquids from the exterior of the mask to theface of the wearer. One or more of these layers may be formed fromexpanded polytetraflouroethylene (PTFE).

A significant technical advantage of the present invention includes aface mask having a filter body with fluid impervious flaps whichcooperate with tie strips to allow the mask to conform to the contoursof the face of a wearer. The filter body and the flaps block liquidspray and aerosols from contacting the portions of the wearer's facecovered by the mask. The present invention allows optimizing thefiltration capability of the mask for resistance to the passage ofliquids and/or aerosols while allowing for a substantially improved fitbetween the periphery of the mask and the contours of a wearer's face.An optically clear visor may be attached to the filter body to protectthe wearer's eyes and portions of the wearer's face which are notcovered by the mask.

Another significant technical advantage of the present inventionincludes a face mask having a filter body with fluid impervious flapswhich allow reducing the surface area of the filter body, if desired,and thus the amount of filter media used to manufacture the mask whilemaintaining the same or an even greater amount of coverage over the faceof the wearer. The fluid impervious flaps allow reducing the amount offilter media used in construction of the mask, if desired, whilemaintaining the same high degree of breathability and high efficiencyfor removing particulate matter and/or aerosols.

A still further technical advantage of the present invention includes aface mask having a filter body with a plurality of pleats formed in thefilter media with at least one of the pleats folded in a reversedirection as compared to the other pleats. The reverse pleat incooperation with the other pleats helps to hold the filter body awayfrom the face of the wearer to increase breathing comfort while wearingthe mask for long periods of time.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and for thefurther advantages thereof, reference is now made to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective view of a face mask and filter bodyincorporating one embodiment of the present invention illustrated on thehead of a wearer;

FIG. 2 is an elevational view with portions broken away of the mask ofFIG. 1 with a cut-a-way showing four layers of material used to form thefilter body of the mask;

FIG. 3 is a perspective view of a face mask and filter bodyincorporating another embodiment of the present invention illustrated onthe head of a wearer;

FIG. 4 is an elevational view with portions broken away of the mask ofFIG. 3 with a cut-a-way showing three layers of material which form thefilter body of the mask;

FIG. 5 is a perspective view of a face mask and visor incorporating afurther embodiment of the present invention illustrated on the head of awearer;

FIG. 6 is an elevational view with portions broken away of the mask andvisor of FIG. 5 with a cut-a-way showing three layers of material whichform the filter body of the mask;

FIG. 7 is a perspective view of a face mask and visor incorporating astill further embodiment of the present invention illustrated on thehead of a wearer;

FIG. 8 is an elevational view with portions broken away of the mask andvisor of FIG. 7 with a cut-a-way showing an alternative securing meansfor attaching the mask and visor to the head of a wearer; and

FIG. 9 is a perspective view showing an alternative embodiment of thepresent invention for attaching the face mask and filter body of FIG. 1to the head of a wearer.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiments of the present invention and its advantagesare best understood by referring to FIGS. 1-9 of the drawings, likenumerals being used for like and corresponding parts of the variousdrawings.

Face mask 12 incorporating the present invention retards the flow ofbacteria, liquids and aerosols from the exterior of mask 12 to the noseand mouth of wearer 14. For purposes of this application, aerosols aredefined as insoluble liquids or particulate matter frequently associatedwithin microbial solutions. The term "fluid" is used within thisapplication to include any gas, liquid, or mixture of gas and liquid.Particulate matter and aerosols may be entrained with such fluids.

The present invention allows optimizing the fluid barrier formed betweenthe periphery of mask 12 and the face of wearer 14 and the filtrationcapability of mask 12 to resist the passage of liquids, particulatematter and/or aerosols while at the same time minimizing resistance tonormal breathing of wearer 14. The present invention allows using onelayer or multiple layers of filter media which may be specificallydesigned to block the passage of aerosols in addition to liquids.

Fastening devices or securing means, such as tie strips 16 and 18, maybe used to removably attach mask 12 to the head and face of wearer 14.Tie strips 16 and 18 are preferably secured to mask 12 at respectivebonded areas 20 and 22. Portions 16a and 18a extending from theirrespective bonded areas 20 and 22 provide a first pair of ties forsecuring mask 12 to the face of wearer 14. Portions 16b and 18bextending from their respective bonded areas 20 and 22 provide a secondpair of ties for securing mask 12 to the face of wearer 14.

As will be explained later in more detail, various types of securingmeans may be used to attach a mask incorporating the present inventionto the face of a wearer. Tie strips 116 and 118 shown in FIGS. 3-8represent one of these alternative securing means. Also, elastic earloops, such as shown in U.S. Pat. No. 4,802,473 entitled Face Mask withEar Loops, may be satisfactorily used with the present invention. U.S.Pat. No. 4,802,473 is incorporated by reference for all purposes withinthis application. As shown in FIG. 8, tie strips 16 and 18 may bereplaced by a continuous loop of resilient material which is disposedwithin but not bonded to flaps 30 and 32.

As best shown in FIGS. 1 and 2, mask 12 includes filter body 28 withflaps 30 and 32 extending respectively from each side of filter body 28.For some applications, filter body 28 may be fabricated in general asdescribed in U.S. Pat. No. 4,635,628 entitled Surgical Face Mask withImproved Moisture Barrier and U.S. Pat. No. 4,969,457. entitledBodyFluids Barrier Mask. Both of these patents are incorporated byreference for all purposes within this application.

Flaps 30 and 32 are preferably formed from fluid impervious materialfolded with a generally U-shaped cross section. Flaps 30 and 32 maysometimes be referred to as C-folds. For one application of the presentinvention, flaps 30 and 32 may be formed from polyethylene filmlaminated to any non-woven material. The non-woven material may also behydro-entangled. For other applications, the polyethylene film may belaminated to any type of material as desired. The polyethylene filmlayer may be color coded to correspond with different applications forusing the resulting face mask.

For other applications, a breathable type film may be used to form flaps30 and 32. For still further applications, flaps 30 and 32 may be formedfrom resilient and/or stretchable materials. Such resilient materialsinclude thermoplastic rubbers which may be extruded or injection moldedas strips or sheets of material. An example of such thermoplasticrubbers is available under the trademark KRATON® from Shell Oil Company.

One of the benefits of the present invention is the ability to formflaps 30 and 32 from materials that have lower cost as compared to thematerial used to form filter body 28. Another benefit of the presentinvention is the ability to form flaps 30 and 32 from a wide variety ofmaterials which provide an enhanced fluid seal with the face of thewearer while providing a comfortable fit during long periods of use.Such materials are available from various suppliers.

Filter body 28 and flaps 30 and 32 are preferably designed to prevent orretard the passage of liquids from the exterior of mask 12 to the faceof wearer 14. It is extremely difficult to construct a mask that willfit the facial configuration of all wearers without constructing themask specifically for each individual face. The use of flaps 30 and 32greatly increases the different sizes and types of faces which can beeffectively protected by mask 12. Forming flaps 30 and 32 from suitableresilient or stretchable material further improves facial fit with alarge number of wearers.

Filter body 28 comprises a plurality of pleats 33, 34 and 35 which allowexpansion of filter body 28 to cover the mouth and nose of wearer 14.The number of pleats 33, 34 and 35 formed in filter body 28 may bevaried to provide the desired fit with the face of wearer 14. Pleat 33is preferably folded in a reverse direction as compared to pleats 34 and35. By providing reverse pleat 33, filter body 28 has an increasedtendency to stand away from the face of wearer 14.

For some applications filter body 28 may be formed without pleats. Forother applications, filter body 28 may be formed with non-collapsingface panels such as shown in U.S. Pat. No. 4,606,341 entitledNon-Collapsible Surgical Face Mask. U.S. Pat. No. 4,606,341 isincorporated by reference for all purposes within this application. Forstill further applications, filter body 28 may be formed from only onelayer of material or from multiple layers of material. Flaps 30 and 32allow for a wide variety of options in selecting material with thedesired breathability and fluid resistance for filter body 28.

The use of reverse pleat 33 in cooperation with pleats 34 and 35 forms alarger breathing chamber as compared to other soft, pleated style maskswhich contact a substantial portion of the wearer's face. The largerbreathing chamber permits cooler and easier breathing associated with"off-the-face" style mask such as shown in U.S. Pat. No. 4,606,341. Thepresent invention allows optimizing the volume of air contained withinfilter body 28 without sacrificing comfort to the wearer or filtrationefficiency.

If the breathing chamber formed by filter body 28 is too large,excessive amounts of exhaled air may be retained within filter body 28at normal breathing rates. By properly selecting the size of filter body28 and flaps 30 and 32, excessive heating of air within filter body 28is minimized and dizziness from prolonged periods of re-breathingexhaled air is also minimized. Since the present invention results in anenhanced fluid seal or barrier between the periphery of mask 12 and theface of wearer 14, incorporating the benefits of an "off-the-face" styleface mask are important for extended periods of wearing mask 12.

As shown by the cutaway portion of FIG. 2, filter body 28 includes fourlayers of material with an external surface of cover stock 36 as theoutermost layer. Inner layer or internal surface 38 which contacts theface of wearer 14 may be constructed of a light weight, highly porous,softened, non-irritating, non-woven fabric, such as Dexter, Inc. productNo. 3768. Inner layer 38 is designed to prevent unwanted materials suchas facial hair, loose fibers or perspiration from contactingintermediate layers 40 and 42 which might cause a wicking effect to drawliquids through filter body 28. Inner layer 38 also provides acomfortable surface for contact with the face of wearer 14.

Intermediate layer 40 preferably comprises a barrier material that iscapable of differentiating between gases and liquids and may be, forexample, Visqueen Film Products' low density polyethylene, VisporeX-6212. Non-wetting materials, such as used to form barrier material 40,have small apertures which prevent liquids with a relatively highsurface tension from passing therethrough yet will allow gases with alow surface tension to pass therethrough. It is preferable to have theapertures as large as possible to allow easy breathing, and yet smallenough to retard or prevent the flow of liquids. Intermediate layer 40is designed to freely pass gases in either direction, while restrictingthe passage of liquids in at least on direction. Filter body 28 isconstructed with barrier material 40 positioned to restrict liquidpassage from the exterior of mask 12. Further description of theconstruction and operation of such barrier material may be found in U.S.Pat. No. 3,929,135 issued Dec. 30, 1975, to Thompson, assigned toProctor and Gamble Co., and is incorporated by reference for allpurposes.

The next intermediate layer is preferably filtration media 42, which maybe, for example, melt blown polypropylene or polyester. Filtration media42 is provided to inhibit the passage of airborne bacteria in eitherdirection which will prevent passage of germs to and from wearer 14.Outermost layer 36 provides the external surface for filter body 28,which may be treated, for example, by spraying with a liquid repellantto render the external surface material resistant to liquids.

Outer layer 36 and filtration media layer 42 serve as an aid to barriermaterial 40 by slowing down any liquid that may be splashed, sprayed orthrown at mask 12. By requiring the liquid to pass through layers 36 and42 prior to reaching barrier material 40, the liquid will have lesspressure and barrier material 40 will be better able to prevent passageof the liquid. Outer layer 36 may be formed from non-woven material suchas cellulose fiber.

Filter body 28 may be formed by bonding layers 36, 38, 40, and 42 witheach other in a generally rectangular configuration. Such bonding ispreferably provided along top edge 44, bottom edge 46 and lateral sides50 and 52, respectively. The corresponding bonded areas 44a, 52a, 46a,and 50a may be formed by sewing, glue, heat sealing, welding, ultrasonicbonding and/or any other suitable bonding procedure. Flaps 30 and 32 arepreferably integrally attached to filter body 28 as part of therespective bonded areas 50a and 52a. Flaps 30 and 32 are preferablyformed from fluid impervious material such as a plastic membrane andfolded with a U-shaped configuration to form an opening to receive tiestrips 16 and 18 therein. Bonded areas 20 and 22 are preferably used tosecure the approximate mid-point of tie strips 16 and 18 withcorresponding mid-points of flaps 30 and 32.

For some applications, flaps 30 and 32 may be formed with a J-shapedconfiguration to receive tie trips 16 and 18 therein. Also, bonded areas20 and 22 may be replaced by other types of restrictions to hold tiestrips 16 and 18 within their respective flaps 30 and 32. The fluid sealbetween the sides of filter body 28 and the wearer's face may beenhanced by reducing the size of bonded areas 20 and 22, or by replacingbonded areas 20 and 22 with other suitable restrictions to retain tiestrips 16 an 18 within their respective flaps 30 and 32.

Top edge 44 of filter body 28 preferably includes an elongated malleablemember 48 provided so that top edge 44 of filter body 28 can beconfigured to closely fit the contours of the nose and cheeks of wearer14. Malleable member 48 is preferably constructed from an aluminum stripwith a rectangular cross section, but may also be a molded or malleablesteel or plastic member. Top edge 44, bottom edge 46 and flaps 30 and 32cooperate with each other to define the periphery of mask 12 whichcontacts the face of wearer 14. Flaps 30 and 32 substantially increasethe area of contact with the face of wearer 14 as compared to a facemask having only lateral sides 50 and 52 in contact the face of wearer14.

Typically surgical style pleated face masks have a generally rectangularor square configuration of approximately seven inches by seven inchesprior to pleating. The length and width dimensions of a typical facemask may vary by plus or minus one-half an inch (±1/2") resulting in aface mask which is often rectangular in configuration as compared to asquare. For some applications, the present invention allows reducing thelength of top edge 44 from seven inches to as short as four and one-halfto five inches. Alternatively, the present invention allows increasingthe length of top edge 44 as desired. Also, the distance from top edge44 to bottom edge 46 when mask 12 has been placed over the face ofwearer 14 may be reduced from seven inches to five and one-half to sixinches. Therefore, flaps 30 and 32, along with other features of thepresent invention allow reducing the total area of the filter mediaassociated with mask 12 from approximately forty-nine square inches totwenty-five square inches to thirty square inches while maintainingapproximately the same effective area. This reduction in area results ina substantial savings in the cost of materials used to fabricate mask 12while, at the same time, maintaining good breathability, high efficiencyfiltration, and providing an improved seal between the periphery of mask12 and the face of wearer 14.

Surgical ties 16 and 18 may be formed from various types of material.For one application of the present invention surgical ties 16 and 18 arepreferably formed from thermally bonded polypropylene having a basisweight of 1.5 to 1.65 ounces per square yard. This particular type ofmaterial can be ultrasonically welded, stitched or heat and pressurebonded in various patterns to provide a resilient securing means for usein attaching mask 12 to the face of wearer 14.

As shown in FIG. 2, a single sonic stitch 24 is provided along thelength of each surgical tie 16 and 18 to provide the desiredlongitudinal stretch and recovery capability. Single sonic stitchpattern 24 allows most of the material used to form surgical ties 16 and18 to be open and free from the associated bonded area. Stitch pattern24 allows surgical ties 16 and 18 to retain their naturally resilientcharacteristics.

Various other types of resilient material may be satisfactorily used toform surgical ties 16 and 18. By providing resilient surgical ties 16and 18, the periphery of face mask 12 will maintain a tight fluidbarrier with the face of wearer 14 over a relatively long period oftime. Talking and other activities by wearer 14 will not compromise theintegrity of the resulting fluid barrier. Laminated strips of materialmay also be used to form ties 16 and 18.

The arrangement of surgical ties 16 and 18 is such that portions 16a and18a extending from top edge 44 may be placed over the top of the head ofwearer 14. Portions 16b and 18b extending from bottom edge 46 may bepositioned around the lower base of the head of wearer 14 as illustratedin FIG. 1. Positioning tie strips 16 and 18 in this manner results incompressing or gathering the respective flaps 30 and 32 to form a flat,flange type fluid barrier with the face of wearer 14. Also, securingsurgical ties 16 and 18 in this manner urges top edge 44 and bottom edge46 into fluid sealing engagement with the contours of the face of wearer14. Surgical tie strips 16a, 18a, 16b and 18b may be positioned on thehead of wearer 14 to provide the optimum pull angle and the optimumamount of force to form the desired fluid barrier between the peripheryof mask 12 and the face of wearer 14. An alternative arrangement for tiestrips 16 and 18 is shown in FIG. 9.

An alternative embodiment of the present invention is represented bymask 112 shown in FIGS. 3 and 4. Masks 12 and 112 are similar except forthe configuration of tie strips 116 and 118 and different layers ofmaterial used to form filter body 128. Flaps 30 and 32 are attached tofilter body 128 in the same manner as previously described for mask 12.However, one end of tie strip 116 is inserted into flap 30 and attachedthereto at bonded area 120. In a similar manner, tie strip 118 is placedwithin flap 32 and bonded at area 122. Thus, when bottom edge 46 offilter body 128 is placed under the chin of wearer 14, tie strips 116and 118 compress or gather the respective flaps 30 and 32 to form afluid barrier with the adjacent portion of the face of wearer 14.

For many applications, tie strips 116 and 118 in cooperation with flaps30 and 32 provide a fluid barrier between the periphery of mask 112 andthe face of wearer 14 which is equivalent to the fluid barrier resultingfrom the use of four tie strips 16a, 18a, 16b and 18b of mask 12. Forsome applications tie strips 116 and 118 could be a single strip ofresilient material extending from bonded area 120 through flaps 30 and32 to bonded area 122.

As illustrated in FIG. 4, filter body 128 includes an outer mask layer136 that is preferably constructed from a spun-bonded polypropylene.Outer mask layer 136 may also be constructed from a bi-component and/orpowder bonded material such as polyethylene or polypropylene, acellulastic tissue, or a spun-bonded polyester. Outer mask layer 136will typically have a basis weight range of 0.5 ounces per yard of 1.0ounces per yard. 0.7 ounces per yard is one of the preferred basisweights for outer layers 136.

Inner mask layer 138 is preferably composed of bicomponent polyethyleneand polypropylene or bicomponent polyethylene and polyester. Layer 138may also be constructed from polyester and/or polyethylene material orcellulastic tissue. Layer 138 will typically have a basis weight rangeof 0.4 ounce per yard to 0.75 ounces per yard. 0.413 ounces per yard isone of the preferred basis weights for layer 138. One or moreintermediate layers of filter media may be disposed between outer masklayer 138 and inner mask layer 138. Selection of the number and type ofintermediate layers of filter media will depend upon the intended useand function for mask 112. In FIG. 4, filter body 128 is shown with onlyone intermediate mask layer 140 which comprises the filter media formask 112. This layer is preferably constructed from amelt-blownpolypropylene, but may be constructed from an extrudedpolycarbonate, a melt-blown polyester, or a melt-blown urethane.

Another alternative embodiment of the present invention is representedby mask 212 with attached visor 90 as shown in FIGS. 5 and 6. Mask 212includes filter body 228 which may be secured to wearer 14 by securingmeans 116 and 118 as previously described for mask 112. Filter body 228is similar to previously described filter body 28 and filter body 128except for the different layers of material used to form filter body228. An important benefit of the present invention includes the abilityto select various types of material to form the flaps and filter bodyassociated with each mask 12, 112, and 212.

For the embodiment of the present invention shown in FIG. 6, filter body228 includes intermediate layer 240 of filter media disposed betweenlayers 236 and 238. For this particular embodiment, inner and outer masklayers 238 and 236 respectively are formed from the same type ofmaterial. However, various types of material may be used withintermediate mask layer 240. For the embodiment of FIG. 6, intermediatemask layer 240 may be formed from an expanded polytetrafluoroethylene(PTFE) membrane. Such materials are manufactured by W. L. Gore &Associates. A more complete description of the construction andoperation of such materials can be found in U.S. Pat. No. 3,953,566entitled Process for Producing Porous Products, issued on Apr. 27, 1976to Robert W. Gore, and U.S. Pat. No. 4,187,390 entitled Porous Productsfor Process Therefor, issued on Feb. 5, 1980 to Richard W. Gore. Thesepatents are incorporated by reference for all purposes within thisapplication. For some applications and operating environments the use offilter media 240 substantially enhances the performance of mask 212 inan aerosol environment.

Face shield or visor 90 preferably comprises a clear, plastic film suchas polyester or polyethylene. Visor 90 is generally dimensioned to fitacross the portions of the face of wearer 14 which are not covered bymask 212. Visor 90 is specifically positioned on filter body 228 toprotect the eyes of wearer 14 from liquid spray and liquid splashes. Theplastic material comprising visor 90 may have a thickness ofapproximately 0.005 inches with enough stiffness to prevent collapse andyet having sufficient flexibility to bend and conform generally with theface of wearer 14. As will be explained later, visor 90 is preferablybonded of filter body 28 near the opposite ends of top edge 44.

Visor 90 preferably has a generally rectangular configuration withrounded corners. The length of visor 90 is preferably selected to beslightly larger than the length of mask 212. The width of visor 90 isselected to be approximately equal to the width of filter body 228 whenexpanded over the nose and mouth of wearer 14. Foam pad 92 is providednear the top of visor 90 to position visor 90 away from the face ofwearer 14. For some applications, foam pad 92 may not be required forproper. fit of visor 90.

Lower edge 96 of visor 90 preferably includes notch 98 which allowsvisor 90 to conform with the nose and face of wearer 14 without causingcreases or wrinkles in visor 90. The dimensions of mask 212, filter body228 and visor 90 may be modified to accommodate wearers having smalleror larger facial features. If desired, a darkened strip of material (notshown) may be placed along top edge 44 of filter body 228 to reduceglare associated with using visor 90. U.S. Pat. No. 5,020,533 entitledFace Mask with Liquid and Glare Resistant Visor describes the benefitsof using such a darkened strip of material. U.S. Pat. No. 5,020,533 isincorporated by reference for all purposes within this application.

Visor 90 is preferably attached to filter body 228 near the oppositeends of top edge 44 proximate to the attachment of flaps 30 and 32 withfilter body 228. Bonded areas 100 and 102 are preferably used to securevisor 90 to filter body 228 at these locations. Various adhesives,ultrasonic seals and/or heat seals may be used to establish bonded areas100 and 102. Ultrasonic seals (sometimes referred to as ultrasonicwelding) may be particularly advantageous for attaching visor 90 tofilter body 228. Bonded areas 100 and 102 cooperate to allow visor 90 toeasily adapt to the contours of the face of wearer 14. Notch 98 in loweredge 96 along with bonded areas 100 and 102 prevent visor 90 from movingup with respect to mask 212 and forming a gap therebetween. Blow-upassociated with normal breathing of wearer 14 and the resulting foggingof visor 90 is substantially eliminated by properly selecting thedimensions and location of malleable strip 48 with respect to top edgeof 44. Malleable strip 48 is preferably positioned in the center of thetop edge 44.

The present invention allows designing mask 212 with the optimumperiphery to fit the face of wearer 14, the optimum dimensions formalleable strip 48 to form an enhanced fluid barrier with the nose andface of wearer 14, and the optimum position for visor 90 with respect tothe eyes and uncovered portion of the face of wearer 14. The presentinvention allows modification to the length of top edge 44 and bottomedge 46 while maintaining the required surface area for efficientfiltration and normal breathing through filter media 240.

The use of barrier materials which block the passage of liquids isparticularly important when mask 212 with visor 90 is worn in anenvironment where wearer 14 may be exposed to "body fluids." Thesefluids such as blood, urine and saliva may contain highly contagiousgerms and viruses. Contact of AIDS-contaminated body fluids with anotherperson's source of body fluids, such as the eyes, nose and mouth, maytransmit the disease. Therefore, it is often preferable to include layer40 and/or 240 which are resistant to the passage of liquids throughfilter body 228 to prevent body fluids from contacting the nose andmouth of wearer 14.

U.S. Pat. Nos. 4,920,960 and 5,020,533 provide additional information onmaterials which may be used for layers 36, 38, 40, 42, 136, 138, 140,236, 238 and 240 and face masks constructed with such materials. Othertypes of liquid barriers may be satisfactorily used with the presentinvention.

Referring to FIG. 5, mask 212 is illustrated as being located on theface of wearer 14. Top edge 44 with malleable member 48 and lower edge96 of visor 90 conform very closely to the configuration of the nose andcheeks of wearer 14. It is important that bottom edge 46 and the chin ofwearer 14 and top edge 44 and the nose and cheeks of wearer 14 fit veryclosely since any leaks result in bypass or blow-by of fluids eitherentering mask 212 or being discharged from mask 212 during use by wearer14. Also, leakage around top edge 44 may cause fogging of visor 90.

Accordingly, resilient surgical ties 116 and 118 have one end attachedat bonded areas 120 and 122 respectively as shown in FIGS. 5 and 6. Thearrangement is such that ties 116 and 118 can be placed over the top ofthe head of wearer 14, as illustrated in FIG. 5, and force applied tocompress or gather the respective flaps 30 and 32. This force urgesbottom edge 46 into sealing engagement with the chin of wearer 14. Atthe same time, compressing flaps 30 and 32 applies force to top edge 44which tends to. move top edge 44 into tighter sealing engagement withthe nose and cheeks of wearer 14. The position of ties 116 and 118 andfilter body 228 in cooperation with flaps 30 and 32 results in theoptimum pull to form a fluid tight barrier or seal between the peripheryof mask 212 and the face of wearer 14.

A still further embodiment of the present invention is represented bymask 212 with attached visor 190 as shown in FIGS. 7 and 8. If desired,visor 190 could be attached to mask 12 or mask 112. Face shield or visor190 preferably comprises a clear, plastic film such as polyester orpolyethylene. Visor 190 is generally dimensioned to fit across thelength of mask 212 and to extend over the eyes of wearer 14.

Visor 190 preferably includes foldable side extensions 192 and 194.Foldable side extensions 192 and 194 are an integral part of and extendfrom main body 196 of visor 190. Edges 193 and 195 of main body 196 arepreferably scored or creased to allow flexible movement of therespective side extensions 192 and 194 relative to main body 196. Asbest shown in FIG. 7 side extensions 192 and 194 cooperate with mainbody 196 to protect the eyes of wearer 14 from liquid splash or liquidspray propelled at an angle relative to the face of wearer 14.

Lower edge 197 of visor 190 includes a different configuration ascompared to lower edge 96 of visor 90. Bonded areas 200 and 202associated with visor 190 are placed lower on the exterior of mask 212as compared to bonded areas 100 and 102 associated with visor 90. Also,notch 198 of visor 190 has a keyhole-type configuration defined in partby slot 201 extending upwardly from lower edge 197 and circular portion203 formed thereon.

An important benefit resulting from the use of flaps 30 and 32 is theability to attach various types of visors to the associated mask and tovary the location of the corresponding bonded area as required toprovide the desired fit between the respective visor and the associatedfilter body.

In FIG. 7, mask 212 is shown with tie 118 extending from bonded area122. The use of ties 116 and 118 was previously described with respectto mask 212 as shown in FIGS. 4 and 6. If desired, ties 116 and 118 maybe replaced by continuous loop of resilient material 216 as shown inFIG. 8. The use of continuous loop 216 eliminates the need for bondedareas 120 and 122. As previously noted, eliminating the bonded areasassociated with flaps 30 and 32 further enhances the fluid barrierformed by the respective flaps and the wearer's face. Also, loop 216 maybe placed about the head of wearer 14 as shown in either FIG. 1 or FIG.9. Flaps 30 and 32 allow the use of loop 216 with masks 12 and 112 inaddition to mask 212.

An alternative arrangement for using tie strips 16 and 18 to secure mask12 with the face of wearer 14 is shown in FIG. 9. As previously noted,the arrangement of surgical tie 16 and 18 is such that portions 16a and18a extend from top edge 44. Portions 16b and 18b extend from bottomedge 46. For some applications it may be desirable to cross portion 16bover portion 16a (not shown) and portion 18b over portion 18a as shownin FIG. 9. The respective portions 16b and 18b may then be tied witheach other over the top of the head of wearer 14. The respectiveportions 16a and 18a may be tied with each other generally about theback of the head of wearer 14. This configuration of tie strips 16 and18 results in portions 16b and 18b cooperating with each other to urgebottom edge 46 of face mask 12 into tight engagement below the chin ofwearer 14. In the same manner, portions 16a and 18a cooperate with eachother to extend in a generally linear continuation from top edge 44 andurge top edge 44 into fluid tight engagement with the face of wearer 14.Also crossing the respective portions 16a and 16b and 18a and 18bresults in additional compression of the respective flaps 30 and 32which further enhances the fluid seal formed between the respectiveflaps 30 and 32 and the adjacent portion of the face of wearer 14. Asdemonstrated in FIGS. 1 and 9, flaps 30 and 32 cooperate with tie strips16 and 18 to provide the optimum pull angle and the optimum amount offorce to form the desired fluid barrier between the periphery of mask 12and the face of wearer 14.

As previously noted, flaps 30 and 32 may have a U-shaped cross-section,a C-fold configuration, or a J-configuration. In addition, flaps 30 and32 may be formed from a single layer of material with the associated tiestrips 116 and 118, or loop 216 threaded through a plurality of smallslits (not shown) in each flap 30 and 32. The small slits would allowthe associated tie strip to gather and compress the respective flapssimilar to a C-fold or U-shaped section.

Although the present invention has been described in detail with respectto alternative embodiments, various changes and modifications may besuggested to one skilled in the art, and it should be understood thatvarious changes, substitutions, and alterations can be made her&towithout departing from the spirit and scope of the invention as definedby the appended claims.

What is claimed is:
 1. A method for preventing liquids and aerosols fromcontacting the face of a person wearing a disposable face mask having aplurality of layers of selected materials, comprising the stepsof:placing each layer of material having a generally rectangular shapein juxtaposition to form a filter body for the mask; connecting thelayers of material along the top edge, bottom edge and the lateral edgesof the generally rectangular shape to form the filter body; attaching alateral edge of a respective flap to each lateral edge of the filterbody; attaching a securing means with each flap on its free lateral edgefor holding the mask on the face of a wearer, wherein the step ofattaching the securing means with the free lateral edge of therespective flaps further comprises the steps of: forming each securingmeans from a surgical tie strip; and bonding only one end of eachsurgical tie strip adjacent to the bottom of one of the respectiveflaps; and attaching a visor near the top edge of the filter body forcovering the eyes of the wearer.
 2. The method of claim 1 furthercomprising the steps of:bonding a first securing means to one of therespective flaps at a location proximate the mid point of the respectiveflap with a first portion of the first securing means extending from theupper part of the respective flap and a second portion of the firstsecuring means extending from the lower portion of the respective flap;bonding a second securing means to the other respective flap only at alocation proximate the mid point of the respective flap with a firstportion of the second securing means extending from the upper part ofthe respective flap and a second portion of the second securing meansextending from the lower portion of the respective flap; crossing thefirst portion and the second portion of each respective securing meansto compress the respective flaps; and tying the second portions of eachsecuring means with each other over the head of the wearer and tying thefirst portions of each securing means with each other behind the head ofthe wearer.
 3. A face mask having a visor to protect the eyes and faceof a wearer, comprising:a non-molded, flexible filter body sized to fitover the mouth and nose of the wearer, the filter body having a top edgearranged to extend across the nose of the wearer, a bottom edge arrangedto extend under the chin of the wearer and lateral edges joining the topedge with the bottom edge; a folded portion of material forming a firstsheet attached to one lateral edge of the filter body and arranged toextend from the filter body; a folded portion of material forming asecond sheet attached to the other lateral edge of the filter body andarranged to extend from the filter body; first and second securing meansattached to the respective first and second sheets and arrange to extendgenerally about the head of the wearer, the first and second securingmeans cooperating with the sheets for urging the top edge and the bottomedge into engagement with adjacent portions of the face of the wearer toprevent undesired fluid flow between the top edge and the bottom edgeand the wearer's face; the first and second sheets cooperating withtheir respective first securing means and second securing means toprevent undesired fluid flow between the lateral edges of the filterbody and adjacent portion of the face of the wearer; and the visorattached near the top edge of the filter body at two bonded areaslocated proximate the attachment of the respective the first and secondsheets with the lateral edges of the filter body; the visor having alower edge with a notch formed therein to allow the visor to graduallybend and approximately conform to the face of the wearer without causingcreasing of the visor, wherein the notch comprises a slot with anenlarged portion formed at the upper end of the slot.
 4. The face maskof claim 3 wherein the visor further comprises;a first foldableextension from one side of the visor; and a second foldable extensionfrom the other side of the visor.
 5. A face mask comprising:a non-moldedfilter body formed from material having a generally rectangularconfiguration and sized to fit over the mouth and nose of a wearer, thefilter body having a top edge and a bottom edge with the top edgearranged to extend across the nose and cheeks of the wearer and thebottom edge arranged to extend under the chin of the wearer; a flapattached to each lateral edge of the filter body and arranged to extendfrom the filter body; a securing means attached to the respective flapsand arranged to extend generally about the head of the wearer, thesecuring means cooperating with the flaps for urging the top edge andthe bottom edge into tight engagement with the wearer to preventundesired fluid flow between the top edge and the bottom edge and thewearer's face; the flaps cooperating with the securing means to preventundesired fluid flow between the respective lateral edges of the filterbody and the face of the wearer; and the securing means furthercomprises a continuous loop engaged with both flaps for gathering andcompressing each flap into sealing contact with adjacent portions of thewearer's face.
 6. The mask of claim 5 wherein the securing means furthercomprises a continuous loop formed from resilient material.
 7. A facemask comprising:a non-molded, flexible filter body formed from materialhaving multiple pleats and sized to fit over the mouth and nose of awearer, the filter body having a generally rectangular configurationwith a periphery including top and bottom edges with the top edgearranged to extend across the nose and cheeks of the wearer, and thebottom edge arranged to extend under the chin of the wearer; theperiphery of the filter body further including a first lateral edge anda second lateral edge opposite from each other and extending between thetop edge and the bottom edge; an elongated malleable member disposedadjacent to the top edge to allow configuring the top edge to closelyfit the contours of the nose and checks of the wearer; a respective flapattached to each lateral edge of the filter body and arranged to extendfrom the filter body; each flap formed from material and folded todefine a generally U-shaped section; a continuous loop of materialdisposed within the U-shaped section of both flaps and arranged toextend generally about the head of the wearer; and the continuous loopcooperating with the flaps for urging at least a portion of theperiphery of the filter body into engagement with adjacent portions ofthe face of the wearer to prevent undesired fluid flow between thefilter body and the wearer's face.
 8. The mask of claim 7 wherein thecontinuous loop further comprises resilient material.